Added verbosity flag (-v) for cp, mv and rm commands

[nicky1038]

Closes #1127

The suggested verbose output is not claimed to be fully identical to the corresponding output in the original commands from coreutils. Though it is very similar, I also tried to make as few edits as possible.

[nicky1038]

I had to force-push the same commit, because I've signed it, so that GitLab could unblock the PR. No code changed

[codecov[bot]]

Codecov Report

Patch coverage: 55.17% and project coverage change: -0.83% :warning:

Comparison is base (a3a7e74) 97.19% compared to head (1e3df2a) 96.36%. Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1129      +/-   ##
==========================================
- Coverage   97.19%   96.36%   -0.83%     
==========================================
  Files          36       36              
  Lines        1354     1375      +21     
==========================================
+ Hits         1316     1325       +9     
- Misses         38       50      +12     

Files Changed	Coverage Δ
shell.js	69.23% <20.00%> (-30.77%)	:arrow_down:
src/cp.js	90.29% <50.00%> (-1.24%)	:arrow_down:
src/mv.js	95.74% <50.00%> (-2.04%)	:arrow_down:
src/rm.js	91.02% <66.66%> (-5.99%)	:arrow_down:

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[nfischer]

It looks like there's a CI bug on the main branch (not a problem with your PR). I opened issue #1130 to work on that.